520 research outputs found
Visible Lagrangians for Hitchin systems and pillowcase covers
We study complex Lagrangians in Hitchin systems that factor through a proper
subvariety of the Hitchin base non-trivially intersecting the regular locus.
This gives a general framework for several examples in the literature. We
compute the fiber-wise Fourier-Mukai transform of flat line bundles on visible
Lagrangians. This proposes a construction of mirror dual branes to visible
Lagrangians. Finally, we study a new example of visible Lagrangians in detail.
Such visible Lagrangian exists whenever the underlying Riemann surface is a
pillowcase cover. The proposed mirror dual brane turns out to be closely
related to Hausel's toy model.Comment: 24 pages, 5 figure, Comments are welcome
Singular fibers of Hitchin systems
In the recent years, Hitchin systems and Higgs bundle moduli spaces were intensively studied in mathematics and physics. Two major breakthroughs were the formulation of Langlands duality of Hitchin systems and the understanding of the asymptotics of the hyperkähler metric on Higgs bundle moduli
space. Both results were considered for the regular locus of the Hitchin system and both results are conjectured to extend to the singular locus. In this work, we make the first steps towards generalizing these theorems to singular Hitchin
fibers.
To that end, we develop spectral data for a certain class of singular fibers of the symplectic and odd orthogonal Hitchin system. These spectral data consist of abelian coordinates taking value in an abelian torsor and non-abelian coordinates parametrising local deformations of the Higgs bundles at the singularities of the spectral curve. First of all, these semi-abelian spectral data allow us to obtain a
global description of singular Hitchin fibers. Moreover, we can construct solutions to the decoupled Hitchin equation on the singular locus of the Hitchin map. These are limits of solutions to the Hitchin equation along rays to the ends of
the moduli space playing an important role in the analysis of the asymptotics of the hyperkähler metric. Finally, we can explicitly describe how Langlands duality extends to this class of singular Hitchin fibers. We discover a duality
on the abelian part of the spectral data, similar to regular case. Instead, the non-abelian coordinates are symmetric under this Langlands correspondence
Interpreting the Interpreters : a Critical Analysis of the Interaction Between Formalism and Transformative Adjudication in Namibian Constitutional Jurisprudence 1990 - 2004
The Security Council of the United Nations adopted Resolution 629 on 16 January 1999, preparing the way for supervised elections and independence for Namibia. A Constituent Assembly elected through a United Nations-supervised election, drafted the Constitution. Namibia became independent from South Africa on 21 March 1990. The dissertation analyses the constitutional judgments of the Supreme and High Courts of Namibia. The interpretive and jurisprudential theories of interpretation of the Namibian superior courts are analyzed. Special attention is given to a post-modern approach known in southern Africa as transformative constitutionalism, developed by American scholar Karl Klare. Klare bases his theory on the proposition that a post-modern constitution cannot be fully understood by using liberal tools or theories of interpretation. University of Cape Town scholar and High Court judge Dennis Davis and his co-worker S Woolman, has a similar approach as Klare and in an enlightening manner refer to the South African constitution as a creole liberal document. The dissertation identifies the Namibian constitution with what Klare calls a post-modern constitution and Davis/Woolman a creole liberal document. While no Namibian court has used the phrases post-modern or creole liberal with reference to the Namibian Constitution, the dissertation identifies several High and Supreme Court judgments where an interpretive model is used that fits the Klare/Davis/Woolman model. The dissertation compares these judgments with other judgments where the superior courts followed the traditional positivist approach. It concludes that both models are part of the Namibian jurisprudential development between independence and 2004. The Supreme Court, the highest court in Namibia, is yet to give an interpretive authority to any of the models. The Namibian legal system follows a strict reliance on the stare decisis rule, which means that the decisions of the Supreme Court are final and binding on government and all the other courts in Namibia. The dissertation identifies several cases where the High Court initially opted for a conservative and/or positivist approach in interpreting rights or freedoms, while the Supreme Court overturned the judgment with a transformative interpretation. The well-known Kauesa case is a good example. The High Court ruled that the freedoms listed in the Constitution are subjected to the laws of Namibia and that dignity is the â highestâ protected right. The Supreme Court rejected the idea that any constitutional right or freedom can be limited by another Namibian law. It also rejected an interpretation seeing rights and freedoms as a pyramid with dignity on top and all the freedoms at the bottom. The Supreme Court opted for a interpretation grounded in the theory of transformative constitutionalism. Freedoms and rights are not organized as a pyramid, but rather a horizontal line of equally important rights and freedoms. The preferential right or freedom needs to be identified in every case depending on the broadest protection of the individual. But, the dissertation points out, there are also cases where the High Court gave a transformative interpretive judgment just to be overturned by a conservative or positivist judgment of the Supreme Court. The well-known Frank case is aq case in point. The High Court found that the word â sexâ as a non-discriminatory category in Artice 10 of the Constitution, also includes sexual orientation. The Supreme Court overturned the judgment by ruling that the word â sexâ only refers to male and female and has nothing to say about sexual orientation. Finally the dissertation concludes that transformative constitutionalism, while not the only interpretive model adhere to by the Namibian superior courts, has been acknowledge as a good model giving the freedoms and rights in the Constitution a broad interpretation, and well-defined protection to Namibians
Where Is the Livestock Future – Plate- or Land-Based? The Potential of Knowledge-Based, Holistic Grazing Concepts for Altering Grazing Livestock Systems
In those days, livestock production heavily depends on feed grown on arable land. Pork production needs most of arable land to gain one kilogram of human-edible protein, followed by chicken, beef production and the dairy sector. In many European countries there is a sharp decline in livestock grazing. Many dairy farms are under pressure to maximize the total annual milk output per cow resulting in increased herd sizes by occupying a minimum of land and feeding of conserved forage of silage and concentrates. Such practices reinforce the competition for arable land for animal feeding as well as grassland intensification by heavily fertilization and frequent cutting to feed the non-grazing cows. This intensification results in unfavourable changes in species composition, loss of biodiversity and important ecosystem services. Moreover, development and widespread adoption of precision farming technologies for grazing systems has been stagnated for many years. The shift towards well-balanced, sustainable grazing systems, that produces more and impacts less, is not easily feasible. Indeed, achieving such grazing systems implies several scientific, technical and socio-economic challenges. These challenges need to be solved in a holistic way in order to facilitate systems integration and transformation into practise. Moreover, the transition requires disruptive innovations for improved pasture utilization by precisely timed grazing pressure for optimizing plant recovery, reducing emissions and maintaining or even recreating structural, biological and functional richness.Thus, an integrated framework combing innovative technologies and concepts is required. The inter-disciplinary project GreenGrass focuses on the development of innovative grazing systems by using novel technologies such as virtual fences and remote sensing in order to bring cows back to pasture and to use the grasslands potential in an efficient and sustainable manner
Improving the Cathodic Biofilm Growth Capabilities of Kyrpidia spormannii EA-1 by Undirected Mutagenesis
The biotechnological usage of carbon dioxide has become a relevant aim for future processes. Microbial electrosynthesis is a rather new technique to energize biological CO fixation with the advantage to establish a continuous process based on a cathodic biofilm that is supplied with renewable electrical energy as electron and energy source. In this study, the recently characterized cathodic biofilm forming microorganism Kyrpidia spormannii strain EA-1 was used in an adaptive laboratory evolution experiment to enhance its cathodic biofilm growth capabilities. At the end of the experiment, the adapted cathodic population exhibited an up to fourfold higher biofilm accumulation rate, as well as faster substratum coverage and a more uniform biofilm morphology compared to the progenitor strain. Genomic variant analysis revealed a genomically heterogeneous population with genetic variations occurring to various extends throughout the community. Via the conducted analysis we identified possible targets for future genetic engineering with the aim to further optimize cathodic growth. Moreover, the results assist in elucidating the underlying processes that enable cathodic biofilm formation
Ordinal Motifs in Lattices
Lattices are a commonly used structure for the representation and analysis of
relational and ontological knowledge. In particular, the analysis of these
requires a decomposition of a large and high-dimensional lattice into a set of
understandably large parts. With the present work we propose /ordinal motifs/
as analytical units of meaning. We study these ordinal substructures (or
standard scales) through (full) scale-measures of formal contexts from the
field of formal concept analysis. We show that the underlying decision problems
are NP-complete and provide results on how one can incrementally identify
ordinal motifs to save computational effort. Accompanying our theoretical
results, we demonstrate how ordinal motifs can be leveraged to retrieve basic
meaning from a medium sized ordinal data set
The unique constitutional position of the Prosecutor-General of Namibia and the effect of the independence of the office on the functioning of the prosecuting authority in relationship with the Ministry of Justice and the Attorney-General
LawLL.M
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